The department studies the distribution, diversity, dynamics and ecophysiology of aquatic photoautotrophic microorganisms (phytoplankton) in Lake Balaton and other lakes with particular emphasis on extreme habitats (e.g. soda pans, hypersaline lakes). Besides nano- and microplankton, the smallest phototrophs (picoplankton) constitute the focus of the research, which are studied with traditional methods as well as fluorescence and molecular biological tools. A new research topic is the study of the aerial spread of pico-sized algae. The group also studies the relationship between underwater light conditions and the primary production of the phytoplankton, at present they conduct research on the effect of underwater light spectrum on phytoplankton pigment composition.
Lake Balaton is an internationally recognized site of long-term ecological research (Lake Balaton LTER site), monitoring the functioning and spatiotemporal changes of phytoplankton dates back to several decades. With regard to functioning, the group concentrates on analysing the relationship between phytoplankton functional diversity and environmental conditions. An algal culture collection is maintained containing various isolates originating from Lake Balaton and other lakes. They recently started research in the field of viruses/virus-like particles affecting cyanobacterial and various algal populations.
Studies on biotic and abiotic factors influencing the growth, spatial and temporal distribution, production of emergent and submerged macrophytes also performed at the department with wide varieties of techniques ranging from genetics to remote sensing.
The department also investigates the cycling of the macro elements (Carbon, Nitrogen, and Phosphorous). One of the main goal is to determine the effect of internal and external nutrient loading and water level fluctuations on the water quality of Lake Balaton. The concentrations of different compounds of nitrogen and phosphorous are regularly measured in the water column and sediments of the Lake. Their uptake are determined with labelled nitrogen (15N) and phosphorous (32P), the competition of bacteria and algae for nutrients are investigated in cultures and in situ experiments. Special attention is paid to cyanobacteria; to their nitrogen fixation and its contribution to the nitrogen supply of phytoplankton and effect on the water quality. A novel method to determine the cyanobacterial biomass based on their phycocyanin content is under development.
The group is involved in scientific projects to develop and improve remote sensing methods of monitoring the water quality and ecological status of inland waters.
The origin of humic substances in the Lake Balaton, their physical-chemical characters, contribution to the organic carbon pool, biological availability, degradation under UV radiation and ecological role are also investigated by our research group.
Natural abundance of carbon and nitrogen stable isotopes are widely used in investigation of the lake ecosystem: detection of organic matter produced by phytoplankton, characterisation of the degradation processes of reed, origin of humic substances and several food web interactions.
The department carries out limnological studies in soda ponds and other wetlands, with special attention to their nutrient cycling and trophic interaction. The mezozooplankton, macroinvertebates and water birds community of soda ponds in the Carpathian basin are also investigated.